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    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>32-递增运算符练习</title>
    <script>
        var a = 10;
        ++a; // ++a  11  a = 11
        var b = ++a + 2; // a = 12  ++a = 12
        console.log(b); // 14

        var c = 10;
        c++; // c++ 11   c = 11
        var d = c++ + 2; // c++ = 11   c =12
        console.log(d); // 13

        var e = 10;
        var f = e++ + ++e; // 1. e++ = 10    e = 11     2. e = 12  ++e = 12
        console.log(f); // 22
        // 后置自增  先表达式返回原值，后面变量再自加1
    </script>
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